What if we apply a very strong magnetic field to an electron so that it's position be a constant. Then if it's position is constant, it's momentum will also be a constant. But it is in violation of Heisenberg's uncertainty principle, so is such an experiment possible?
4
-
$\begingroup$ The premise is not correct. If we try to artificially confine the electron to a precise position, then its momentum will become completely uncertain (precisely because of the uncertainty principle), and it will necessarily escape from confinement. $\endgroup$– Dmitry BrantCommented Oct 31, 2013 at 13:38
-
$\begingroup$ But even if the magnetic field is very very strong? $\endgroup$– annaversion2Commented Oct 31, 2013 at 13:48
-
$\begingroup$ I can't see where and why is my misunderstanding. $\endgroup$– annaversion2Commented Oct 31, 2013 at 13:48
-
2$\begingroup$ A magnetic field won't hold the electron in place. It will just constrain the electron to move in a circle. $\endgroup$– John RennieCommented Oct 31, 2013 at 15:52
Add a comment
|
1 Answer
$\begingroup$
$\endgroup$
If you apply a very strong magnetic field, its position will be in average constant with little deviation (motion is very small circles) but that says nothing about its momentum, because it may be rotating at just any velocity.
Note that that's true even considering classical mechanics. Obviously for quantum mechanics Heisenberg's principle holds.
Also note that all this applies only in the plane perpendicular to the magnetic field; motion along the magnetic field is free.
